Multistage compressor

ABSTRACT

The axial-flow low pressure section and radial-flow or diagonalflow high pressure section are separated by a recooler in which the working fluid is first deflected outwardly from the rotor, spread fanwise in a channel around and perpendicularly of the rotor, then deflected towards the rotor and fed perpendicularly through a channel to the compressor axis. In addition, a cooling element is disposed in one of the channels for cooling of the working fluid.

United States Patent Strub a1. 5, 1974 [5 MULTISTAGE COMPRESSOR2,619,279 11/1952 Schaer 415 179 2 'l 1751 Inventor: Rene S919 wmefihur,Swnzeriand 513531323 21132? 1 55211321251? iii/133 I 1 Assigneel Brown een FOREIGN PATENTS OR APPLICATIONS Tufmmmhmery lunch 215,474 10 1941Switzerland 415 179 Switzerland {22] Filed: Jan. 17, 1972 PrimaryExaminerHenry F. Raduazo Attorney, Agent, or FirmKenyon & Kenyon Reilly[21] Appl. No.. 218,161 Carr & Chapin [30] Foreign Appiication PriorityData ABSTRACT Jan. 20, 1971 Switzerland 844/71 The xi -fl w low pr recti n nd radial-flow or diagonal-flow high pressure section areseparated by a [52] U5. Cl 415/149, 415/143, 415/179 re ool r in whichthe working fluid is first deflected [51] Int. Cl. F0411 15/00, F04d27/00, F04d 29/58 outwardly from the rotor, spread fanwise in a channel[58] Field of Search 415/177, 178, 179, 149 around and perpendicularlyof the rotor, then flected towards the rotor and fed perpendicularly[56] References Cited through a channel to the compressor axis. inaddition, UNITED STATES PATENTS a cooling element is disposed in one ofthe channels 2,396,484 3/1946 Allen et al. 415 179 for coolmg of theworkmg fluld' 2,540,991 2/1951 Price 415/179 7 Claims, il Drawing Figuref"""""""""'1"""""""'Zl 30 32 ,12 29 1 \k n I H PATENTEDMR 5M4 3L795L45aOOOOO OOOOOOO 0000000 000000 0000 OOOOOOO 0000000 000000 000000 OOOOOO'OOOOOOO ooooo ooooooa 0000000 0000000 OOOOOO o 000 000000 ocoooooooooooo MULTISTAGE COMPRESSOR This invention relates to a multistagecompressor.

Heretofore, multistage compressors have been known to have a rotor 'onwhich an axial-flow lowpressure section is disposed with stages forcompressing a working fluid without cooling to a maximum permissibletemperature. The low-pressure section has been followed by a radial-flow(or diagonal-flow) highpressure section while a recooler has beendisposed in the fluid flow path between the low-pressure section andhigh-pressure section. Compressors, of this kind are known, for instancefrom Motortechnische Zeitschrift, Jahrgang 13, Nr. 2, February 1952.

However, these known compressors have been of relatively longdimensional lengths. As a result, such has resulted in excessivewhirling. Also, the number of radial-flow stages has been limited.

Accordingly, it is an object of the invention to provide a compressor ofvery small dimensions.

It is another object of this invention to reduce whirling in acompressor.

It is another object of this invention to be able to use two or moreconsecutive radial-flow stages without axial reversal of the workingfluid.

Briefly, the invention provides a multistage compressor having a rotor,an axial-flow low-pressure section and a radial-flow high pressuresection with a means for deflecting a working fluid leaving thelow-pressure section first away from the rotor and then towards therotor for entry perpendicularly into the radial-flow high pressuresection as well as a cooling element for cooling the working fluidflowing into the high-pressure section. The means for guiding theworking fluid between the low-pressure and high-pressure sectionsincludes a first deflector section, a first channel, a second deflectorsection and a second channel, in that order. The first deflector sectiondeflects the working-fluid flow outwardly away from the rotor. The firstchannel spreads the flow out fanwise around and perpendicularly to thecompressor axis. The second deflector section deflects the flow backtowards the shaft and the second channel supplies the flow to thehigh-pressure section entry perpendicularly to the compressor axis. Atleast one-of the two channels has at least one cooling element disposedtherein.

These and other objects and advantages of the invention will become moreapparent from the following detailed description and appended claimstaken in conjunction with the accompanyingv drawings in which:

The drawing illustrates a cross-sectional view of a multistagecompressor according to the invention.

Referring to the drawing, the multistage compressor has a rotor 1 onwhich six axial sets 2-7 of axial-flow blades are mounted in a firstsection and three radialflow rotors 8-10 in a second section. Extendingaround rotor l is a casing 11 having an entry channel 12 for the entryof fluid for compression. A channel 13 is disposed at the opposite endfor exiting of compressed fluid. The axial-flow section of thecompressor comprises a blade carrier 14 in which seven sets l'2ll ofguide blades are mounted. Each individual blade of the sets l5-2l has aroot which is mounted in the blade carrier and on which bent levers 24,engaging in circular grooves 22 in adjustment cylinder 23, are disposed.A toothed rack 25 is positioned at the bottom of the cylinder 23 toenable the cylinder 23 to be'adjusted to suit operating requirements bymeans of a pinion 26 of a motor 27.

In addition, the adjustable guide blades 15-21 which are adjustablearound a radial axis are followed by at least one axial-flow stagehaving an adjustable exit guide blade 21 and a non-adjustable entryguide blade for the channel 29.

Disposed between the last set 21 of axial-flow rotor blades and thefirst radial-flow rotor 8 is a deflector part 28 which is connected tothe casing l1 and in which the axial flow from the first section of thecompressor is converted into an outwardly directed radial flow.Following section 28 is a channel 29 which is directed radially outwardsand which acts as a diffusor and through which the fluid flows to gothrough a second deflector section 30 into a second channel 31. Thesecond channel 31 extends radially inwards. After further deflection,the flow enters the first radial flow rotor 8. The inwardly directedchannel 31 has cooling elements 32 which reduce the heat of compressionacquired by the fluid in the axial-flow section of the compressor. Thereis, therefore, recooling of the fluid being compressed, and so a veryhigh compression ratio can be used as early as the first radial-flowstage before any further cooling is given by elements 33. Aftercompression in the next rotor Q, the fluid is recooled by elements 34before being compressed to its final pressure by rotor 10.

Thecooling-elements 32 together have a larger cooling area than do theelements 33, 34, since the axialflow section of the compressorcompresses the fluid to the maximum permissible temperature, whereas ina radial-flow stage only the greatest pressure difference, with areduced temperature rise occurs.

The diffusor type radial-flow channel 29 can have appropriate guideelements which can also be devised as cooling elements.

The invention thus provides a compressor which can be constructed ofrelatively short lengths. Because of this, the rotor bearings can beclosely spaced with a resultant reduction of whirling. Also, a number ofradialflow stages can be used as there is no axial reversal of theworking fluid flow.

What is claimed is:

1. A multistage compressor comprising a casing;

a rotor within said casing;

an axial-flow low-pressure section having a plurality of stages aboutsaid rotor for compressing a working fluid without cooling to a maximumpermissible temperature;

a radial-flow high-pressure section downstream of said low-pressuresection on said rotor;

means within said casing between said low-pressure section and said highpressure section including a first deflector section for deflecting theworking fluid perpendicularly outwardly away from said rotor, a firstchannel for thereafter spreading out the working fluid flow fanwisearound and perpendicularly to said rotor, at second deflector sectionfor deflecting the fluid perpendicular to said rotor towards said rotorand thereafter into said highpressure section; and

at least one cooling element in said means for cooling the working fluidpassing through said means to reduce the heat of compression acquired bythe flow in said axial-flow section and to achieve a very highcompression ratio prior to flow of the fluid into said radial-flowsection.

2. A multistage compressor as set forth in claim 1 wherein said coolingelement is disposed in one of said channels.

3. A multistage compressor as set forth in claim 1 wherein said stagesincludes axial flow blades for compressing the working fluid withoutrecooling.

4. A multistage compressor as set forth in claim 3 wherein said bladesof at least the first stages are adjustable about a radial axis.

5. A multistage compressor as set forth in claim 5 wherein at least onestage downstream of said adjustexit guide blade and said means.

1. A multistage compressor comprising a casing; a rotor within saidcasing; an axial-flow low-pressure section having a plurality of stagesabout said rotor for compressing a working fluid without cooling to amaximum permissible temperature; a radial-flow high-pressure sectiondownstream of said lowpressure section on said rotor; means within saidcasing between said low-pressure section and said high pressure sectionincluding a first deflector section for deflecting the working fluidperpendicularly outwardly away from said rotor, a first channel forthereafter spreading out the working fluid flow fanwise around andperpendicularly to said rotor, a second deflector section for deflectingthe fluid perpendicular to said rotor towards said rotor and thereafterinto said high-pressure section; and at least one cooling element insaid means for cooling the working fluid passing through said means toreduce the heat of compression acquired by the flow in said axial-flowsection and to achieve a very high compression ratio prior to flow ofthe fluid into said radial-flow section.
 2. A multistage compressor asset forth in claim 1 wherein said cooling element is disposed in one ofsaid channels.
 3. A multistage compressor as set forth in claim 1Wherein said stages includes axial flow blades for compressing theworking fluid without recooling.
 4. A multistage compressor as set forthin claim 3 wherein said blades of at least the first stages areadjustable about a radial axis.
 5. A multistage compressor as set forthin claim 5 wherein at least one stage downstream of said adjustableblades includes non-adjustable blades.
 6. A multistage compressor as setforth in claim 1 wherein said high-pressure section includes at leasttwo radial-flow rotors and a second cooling element between said radialflow rotors for cooling the working fluid passing therebetween.
 7. Amultistage compressor as set forth in claim 1 which further includes anadjustable exit guide blade downstream of said stages of saidlow-pressure section and a non-adjustable entry guide blade between saidexit guide blade and said means.